Spray gun



Oct. 3o, 192s. 1,689,848

S. F. ANDERSON SPRAY GUN Filed June 25, 1924 Patented Oct. 30, 1928.

UNITED STATES PATENT oFI-lcl-z.

SWAN F. ANDERSON, OF BOCKFORD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T PEEBLESS PNEUMATIC SYSTEMS, INC., 0F CHICAGO, ILLINOIS.

SPRAY GUN.

Application led June 23, 1924. Serial No, 721,719.

This invention relates t-o air brushes or spray guns as they are commonly known, for atomizing and spraying by air pressure such materials as paints, fillers, enamels, varnishes, shellacs, dyes, stains, bronzes, alumivnums and in fact all liquid or ilui'd material which it is desired to'spread onto a surface for coating or any finishing purpose. The present invention is, more particularly, an

l0 improvement on that disclosed in my copending application Serial No. 600,241, filed November 11, 1922.

One ot' theobjects of the present invention is to provide an improved vspray gun for handling materials of heavier consistcucies but. adapted also for any of the lighter or iiner materials.Y In other words my improvements enable the spraying of a greater variety of materials. This is accomplished primarily by the provision of a hollow needle valve for delivering a primary jet of air into an atomizing chamber in the discharge passage of a material-delivery nozzle and delivering a secondary stream of air peripherally about the material discharging from said passage through a central orifice, and finally delivering supplemental supporting jets of air onto the discharging spray from Yopposite sides thereof for the purpose of further atomizing the material and for ilatvtening the spray into a line delivery in which the material is subst-antially uiniformly distributed from end to end. I have also aimed to provide an adjustment for regulatinor the i'low of secondary air independently o? the primary air for purpose of obtaining umormity in the distribution of materials of different consistencies.

Another object is to provide an lmproved 40 nozzle, characterized by its few parts, its simple and practical construction, and the embodiment of a primary and a secondary delivery of air for the purpose described.

A further object is to provide improved means for controlling the delivery of the primary and the secondary air. Still another- .object is to so construct the parts that they may be `produced at a comk paratively low cost and will serve in a practical and etlicient manner the purposes 1ntended.

Other objects and attendant advantages l will be appreciated by those skilled in this art as the invention becomes better understood by reference to the following descrip'- tion when considered in connection with the accompanying drawing in which- Figure l, is a side elevation of a spray gun embodying my invention;

Fig. 2, is a longitudinal sectional view through the spray gun, showing its parts in the normal position;

Fig. 3, is an enlarged section through the nozzle end showing the needle valve retracted to the open position for spraying; and

Figs. 4 and 5, are sections taken substantially on the lines 4-4 and 5-5 respectively of Fig. 2.

Referring more particularly to the drawing, it will be observed that'the body on which the several operating parts are mounted is in the form of a one-piece casting, shaped to provide a handle and a head portion 6 and 7 respectively, connected by an intermediate barrel-like portion 8. This onepiece body provides a rigid supporting structure for the several cooperating parts and is particularly well adapted for carrying them in the operative relation which will be presently described.

The material to -be atomized will be delivered through a passage 9 into the inlet chamber 11 in the head 7 through a suit.- able hose connection and ata constant pressure. The air pressure will be admitted to the body through a hose connected to a suitable source of supply and attached prefer-- bly to a threaded nipple 12 on the handle portion 6, in which is formed an air supply inlet. passage 13 coaxial with the material inlet chamber or passage 11.

According to my invention means is provided for deliverin a primary jet of air into an atomizing c amber through a hollovv needle valve receiving its supply of air in this instance from the passage 13, into which chamber material is delivered from the material supply passage 11 at a rate regulatedby the position of the needle valve. The material will be atomized by such primary air and discharged through a central orifice and after leaving such orlfice the material will be further.atomized by a second- -ary atomizing action produced by a secondsource as the secondary air. The parts employed in directly performing the function just described are embodied in a nozzle structure mounted on the head 7, which structure v.will now be more fully described.

A material-delivery nozzle which ,will be referred to as the color nozzle, designated enerally by 14 is in the form of a hexagonal y 'having a reduced threaded end 15 screwed into the material inlet passage 11 and an opposite externally threaded end 16 terminating in a conical discharge nozzle 17. Said body 14 has a central bore or passage 18 which communicates at one end with the The secon r clamp in position a fiat spray nozzle the body material inlet passage 11 and at the opposite end with a conical passage 19 in the'fnozzle portion 17 terminating in a discharge orifice 21. The body 14 is hexagonal merely to facilitate tightening it in the head 7. The conical passage 19 provides an atomiziiig chamber in which a jet of primary air is delivered into the material as will bev presently described. Onto the threaded end 16 of the color nozzle is screwed a secondary air nozzle designated generally b 22 having a cylindrical periphery 23 an a flanged end 24 the periphery of which is knurled for convenlence in tightening said nozzle in position.

(la-ryair nozzle serv-es to hold or of which is designated generally by 25. This body provides an annular air c amber 26 about the nozzles 14 and 22 and seats at 27 against the head 7 and'is engaged at its oposijteend b the flange 24 and clamped therey so as to held in position. The second- Aary air nozzle 2 2 hasa plurality, four in the present instance,u oflequ'ally spaced radial ports 28 connecting the air chamber 26wi-th. an air chamber 29 surrounding the nozzle por tion 17 and terminating in "a secondary air discharge orifice 31 concentric with the dischargey orifice 21. The fiat spray nozzle l25` is sha to provide a pair of diametrically opposite passages 32 leading from the air chamber 26 in divergin relatioir and terminati-ng in converging ischarge'orifices 33 adapted for delivering supplemental jets of air onto the atomized material discharging from the central orifice 21 for the purpose of fiattening` tli'e spray into a. line-like delivery. By `loosening the nozzle member 22 the flat -spray nozzle 25 may be rotated or lswivelled for the purpose of changing the VThe needle valve extends rearward from the passage 11 through a packing gland 36 and terminates at its rear end in a cylindrical por-- tion 37 which slidably fits in a tubular valve stem 38 in turn axially slidable in a. sleeve or bushing 39 fixed in the handle portion 6 of the body coaxialwith the air-supply passage 13. The valve stem 38 nhas a valve 41 which seats against the rear end of the bushing 39 and is normally held seated by a compression spring 42 the outer end of which abuts against'a perforated plug 43 threaded in the nip-ple 12. When the valve 41 is unseated by drawing lback a trigger 44 as will be presently described the air supply will be admitted into the bushing andto apassage 45 leading thereom which passage is connected by a passage 46 in the barrel-portion 8 to the annular chamber 26Iabove described, thereby providing air for the seconda-ry nozzle and for the supplemental jets. The air thus vadmitted into the bushing 39 by unseating the valve 41 Will also enter the rear end of the hollow needle valve through diametrically opposed ports 47 in the tubular valve stem 38 connecting'the interior of said valve stem 38 with the interior of thevbushing 39, it being not-ed that the valve stem is turned down intermediate the ports 47 and the valve seat 41 to provide for communication with the passage 45 and the ports 47 from the air supply paspered at 48 so as to provide a graduated opening permitting` only a small volume of air to enter the bushing 39 and passages communicating therewith when the valve 41 is initially opened and lwhereby the air sup-ply will be increased with the. opening movement of the valve. It will thus be manifest that upon unseating the valve 41 air/wilhbe delivered through the needle valve, the secondary air nozzle 'and the supplemental air jet orifices.

The trigger 44 not only unseats the valve 41 as above mentioned but also unseats the needle valve 34. The means by which this is accomplished will now'be described.- The trigger straddles the barrel-portion 8 ofthe zgun body and is pivotally attached'thereto at 49.

has a crosshead 53 against which the front cud of the Valve stem 38 bears, a washer 54 being interposed and having a finished seat 55 engaged by the forward end of said Vvalve stem for prevent-ing leakage of air. It`will be manifest that by drawing t-he trigger 44 rearwardly the valve stem 38 will be similarly moved so as to unseat the valve 41. The arms of the yoke 51 have a lost motion connection with the hollow needle valve so that the latter will be opened at a predetermined point subsequent to the opening of the Valve'41, thereby producing a discharge of secondary air through the orifice 31 before the material to be atomized is discharged. This connection comprises a crosshead 56 fixed to a.' sleeve 57 threaded onto the hollow needle valve and having a bearing support in a lug 58 integral with the body barrel portion 8, the crosshead having diametrically opposed fino'ers 59 disposed in slots 61 in the arms of the yoke 51. A coiled compression spring 62 surrounding the sleeve 57 and acting between the lug 58' and the erosshead 56' urges the latter forward for seating the tapered end of t-he needle valve 34 against the conical wall of the passage 19; By turning the needle valve in the sleeve 57 the particular point at which the needle valve will unseat-with respect to the unseating of the valve 41 may bel varied'. In the present inst-ance the needle valve may be turned by means of a knu'rled disc 6G mounted on said needle valve between the yoke and the packing gland or stuffing box 3G so as to turn with the needle. valve butl slide leiigthwise thereon, the needle valve being flattened at 67 for this purpose and the disc being shape to engage the flatsides.

The operation of the spray gun is as follows: Parts are shown in the normal position in Fig. 2, in which the needle valve 34 is held seated by the spring 62 and the valve 41 is held seated by the spring 42. Assuming that the passage 9 is connected to a. source of material supply, which .is under a suitable pressure, and that the passage 13 is connected with a source of air supply at a suitable pressure, when the trigger 44 is drawn back the valve 41 will be unseated allowing air to be delivered through the needle valve orifice 35 and through the secondary air discharge orifice 31 and the converging discharge orifices 33 as described above. The flow of air through the orifices 31 and 33 may be regulated with respect to the flow through the orifice 35 by adjustment of a valve stem 68 in the passage 45, this adjustment being particularly desirable when setting the spray gun for the use of materials of different consistency. As above mentioned the initial movement ofthe trigger does not, unless so set, open the needle valve. When the needle valve 34 does open after the lost motion movement between the yoke 51 and the crosshead 56, the

' material to be atomized will be delivered into the chamber formed by the conical passage 19.

' mary atomization taking place before the {inaterial reaches the discharge orifice 21. The discharge of primary air into the chamber 19 will moreover produce an injector action which aids in the flow of material through the color nozzle and is especially advantageous in air brushes of this type when materials of comparatively heavy consistency are used. The partially atomized material discharging through the central orifice 21 will be subjected to the action of the secondary air which disj charges peripherally thereabout through the orifice 31. It will be noted that the tip of the nozzle portion 17 indicated by 69 is cylindrical for 'a short distance so as to cause the flow of secondary air to intersect the spray discharging from the orifice 21 at a slight disy tance in front there-of at which point the discharging material issues in a diverging spray. By reason of this mixture of the secondary air with the primary mixture a very effective atomizing action is obtained. The discharging spray will be further atomized by the action of the supplemental jets of' air delivered through the orifices 23 which cause the spray to be flattened into a. line-like delivery, the major axis of which, with. the present setting of the flat spray nozzle, will be horizontal. It will be noted thatl the valve opening movement of the trigger is limited by an adjustable set screw stop 71 which strikes againstI the forward edge of the handle.

The construction disclosed herein is especially desirable because practically all of the working parts are coaxial with the axis of the nozzle and the valves and because these parts are mounted on a one-piece body in such manner that they are maintained in alignment. This facilitates nmnufzu-ture and assembly of the spray gunand enables the cost of production to be reduced to a minimum. It also insures the maintenance of well fitting valve seats and prevents such Wear-as will cause undue leakage ot' air. The extension of the hollow needle valve into the tubular valve stem is a feature of my invention which makes for simplicity in construction and o1 cration. Another feature of importance is the.. nozzle construction by which atomization of the material is started before it leaves the color nozzle. In. other words the material is also initially atomized in the clnunber 19 by the action of the primary air. Still another feature is the use of a hollow needle in the manner disclosed causing an injector ing against stoppage and variation in the iow which might occur in the absence of such construction. My improvements are therefore especially adapted for handling materials Which do not fiow easily. The construction is however equally well adapted for handling materials of thinner consistency. It is believed that the foregoing conveys a clear understanding of the objects prefaced above and, while I have illustrated but a single working embodiment, it should be understood thatchanges might be made in details of construction without departing from the spirit and scope of the invention as expressed in the appended claims, in which- I claim:

' l. In a spray gun, in combination, a body having a material-supply passage and an'airsupply passage, a color nozzle threaded into said material-supply passage and being peripherally threaded at its extended end and terminating in a nozzle portion having a 'conical interior passage and a conical exterior surface and a discharge orifice from said inn terior passage, a needle valve in said conical passage adapted to regulate the flow ofimaterial therethrough, a secondary air nozzle th'readedly engaged on the said extended threaded end of the color nozzle and providing an air chamber about the conical end thereof converging to a central discharge oriiice concentric with the discharge orifice of the color nozzle, and a fiat spray nozzle body held in position by said secondary air nozzle and providing an annular air chamber about the latter communicating with said air supply passage in the body, said flat spray n ozzle body having diametrically disposed air passages which diverge from said annular air chamber and terminate in converging oriices for delivering supplemental ets of air for flattening the spray discharging from said central orifice.

2. A spray gun comprising, in combination, a body having a handle at one end and a nozzle-supporting head at the opposite end, 'said head having a material-supply passage and said handle having an air-supply passage in coaxial relation, a material-delivery nozzle on said head connected with said passage therein and having a hollow needle valve passng axially through and rearwardly beyon concentric with the material-delivery nozzle and receiving air pressure from said airsupply passage in the handle, a tubular valve stem slidable axially in said air-supply passage and having a valve for closing the passage and adapted to open it b rearward movement therein, the rear end o the hollow needle valve extending into the tubular valve stem and adapted to receive air pressure when the valve stem is moved rearwardly to an open position, and a trigger connected to the said'passage, an air-delivery nozzle needle valve and valvev stem for imparting opening movement thereto.

3. A spray gun as set forth in claim 2, including spring means fornormally holding the tubular valve stem and the needle valve in a closed position, and means connecting the trigger' with the tubular valve stein and the needle valve to move said tubular valve stem for opening the air supply passage prior to unseating the needle valve.

4. A spray gun as set forth in claim 2, including a bushing in the air-supply passage in which bushing the tubular valve stem is slidably mounted and against which the valve on said stem seats.

5. A spray gun as set forth in claim 2, including a thrust connection between the forward end of the tubular valve stem and the trigger through the intermediary of a part slidable on the needle valve.

6. A spray gun as set forth in claim 2, including means in the connection between the air-supply passage and the air-delivery nozzle for regulating the How of air to the latter independently of the flow of air to the needle valve.

7. A spray gun comprising, in combina.- tion, a one-piece body having a handle and a "nozzle-supporting head joined by a barrel portion, said head having a material-supply passage and said handle having an air-supply passage in coaxial relation below said barrel portion, a material-delivery nozzle on said head connected with said passage therein and having a hollow needle valve passing axially through and rearwardly beyond said passage,

an air-delivery nozzle concentric with the material-delivery nozzle, the barrel portion having a passage connecting the air-supply passage in the handle with the air-delivery `nozzle for supplying air thereto, a` tubular valve stern slidable axially inthe air-supply passage in the handle and having a valve normally closing said passage, the needle valve extending into the tubular valve stem and adapted to receive air pressure for the material-delivery nozzle whenthe air-supply valve is opened, and a. trigger connected with said tubular valve stem and needle valve for,

imparting opening movement thereto.

8. In a spray gun, in combination, al head having a material-supply passage; a material-delivery nozzle comprising a body having -a threaded end engaged in said passage and an opposite threaded end terminating in a conical nozzle portion having a conical passage terminating in a central discharge oritice, and a hollow needle valve having a conical end normally seated in said conical passage and adapted to be withdrawn so that the discharge orifice of the needle valve is po-l sitioned within said conical passage which latter constitutes a primary atomizing chainber; a secondary air nozzle comprising a cy lindrical body threaded onto the extended threaded end of the material-delivery nozzle and having a. flanged outer end and shaped to provide a conical air chamber around the conica-lend of the material-delivery nozzle, said conical air chamber terminating in a discharge orifice concentric with that of the material-delivery nozzle and having ports communicating with the periphery of the cylindrical body of the secondary nozzle; a flat spray nozzle comprising a body embracing the secondary air nozzle and clamped in position by engagement with the flanged end of said secondary air nozzle, said flat spray f' nozzle body providing an annular air chamber communicating with said ports in the secondary air nozzle and having diametrically opposed air passages leading from the annular air chamber and terminating in converging discharge orifices adapted for delivering supplemental jets of air intersecting the spray discharge from the nozzle proper.

y 9. In a spray gun, in combination, a nozzle structure comprising a material delivery nozzle and a secondary air delivery nozzle, a trigger operated needle valve for regulating the flow of material ythrough said material delivery nozzle, and means for supplying air to said secondary air nozzle including an air valve coaxial and telescoping with the end of the needle valve.

l0. A spray gun as set forth in claim 9, including a gun body having a head and a handle portion, said nozzle structure being arranged on the head portion and said air valve in the handle portion, said body having a material inlet passage communicating with the material delivery nozzle, froni which passage said needle valve extends rearwardly and into telescoping connection with said air valve in the handle portion, a packing for the needle valve at the point where it leaves the head portion of the body, and a trigger structure on the body operatively connected with the needle valve and said air valve member intermediate said head and handle portions. 11. In a spray gun, in combination, a gun body having a material inlet passage, a material delivery nozzle externally threaded at opposite ends one of which is engaged in said' inlet assage, a nozzle portion on the other threa ed end of said body terminating in -a central material discharge orifice concentric with the adjacent threaded end, an air nozzle threaded on the outer end of said material nozzle and providing an air discharge orifice peripherally about and concentric with said material discharge orifice, and an air nozzle body embracing the material nozzle and said air nozzle and adapted to be clam ed in position by tightening the latter on t e material nozzle, said air nozzle body having diametrically opposed converging discharge orifices adapted for delivering supplemental jets of air into the atomized material discharging from the central orifices, whereby said air orifices will be held in determined alignment with the material discharge orifice.

12. In a spray gun, in combination, a material delivery nozzle externally threaded 1 11 coaxial relation to its material discharge orilice, an air nozzle body threadingly engaged on the threaded portion of said material nozzle and having an air discharge orifice disposed coaxial with and peripherally about said material discharge orifice, and a supplemental air nozzle body embracing the tiret mentioned air nozzle body and adapted to be clamped in position by turning the latter on the threaded portion of the material nozzle, said supplemental air nozzle body having diametrically opposed converging air delivery orifices for producing a fan-shaped spray and being held in determined relation to said air and material delivery oriiices by the clamping action of the first mentioned air nozzle body.

13. -In a spray gun, in combination, anozzle structure including an atomizing chamber having a central material discharge orifice and a secondary air chamber having an annular air discharge orifice concentric with and surrounding said material discharge orifice for delivering secondary air peripherally about and into the material discharging through said central orifice, a trigger-operated hollow needle valve for regulating the flow of material through said central orifice and adapted to discharge primary air into said material for effecting an initial atomizatioii thereof, means for delivering air to said hollow needle valve and said secondary air chamber vincluding a tubular valve stem telescoping with the end of the needle valve remote from its discharge end, means providing air communication between said valve stem and said secondary air chamber, said tubular valve stem having a valve communicating vwith a source of air'supply and being movrounding said materiali-*discharge orifice fordelivering secondary air peripherally about and into the material discharging through said central orifice, a trigger-operated hollow needle valve for regulating the flow of material through saidicentral orifice and adapted to discharge primary air into said material for eilecting an initial atomization thereof, means for delivering air to said hollow needle valve and said secondary air chamber including a tubular valve stem telescoping with the end of the needle valve remote from its discharged end, means providing air communication between said Valve stem and said seeondary air chamber, said tubular valve stem having a valve communicating with a source of air supply and being movable axially independently of the needle valve for admitting air tothe secondary air chamber and to the hollow needle valve, and trigger operable means bearing directly against said air valve stem for unseating it and havnga lost-motion connection With said needle Valve for unseating it Subsequently to said air valve stem.

SWAN F. ANDERSON. 

